I. Field of the Invention
The present invention relates generally to drying systems and, more particularly, to a wet coal drying apparatus.
II. Description of the Prior Art
In coal burning furnaces of the type commonly used for the production of electrical power, the coal is typically stockpiled at a suitable storage area and transported to the furnace by any of a number of means, such as conveyor systems, trucks, and the like. However, prior to loading the coal into the furnace, the coal is pulverized which simultaneously decreases ignition time for the coal and increases burning efficiency.
One disadvantage with these previously-known arrangements is that the coal often becomes wet from rain, snow, or the like. The wet coal is difficult to ignite in the furnace and this decreases the burning efficiency of the coal. Even more seriously, after the pulverization of the coal, the granular coal tends to freeze and lump together during cold weather which makes the coal not only difficult to burn, but also tends to clog the conveyor means between the pulverizer and the furnace.
A still further problem with these previously-known coal burning furnaces is that in winter the coal is cold and wet when it is loaded into the furnace. Consequently, energy is consumed and effectively lost in the furnace due to the necessity of heating the wet and cold coal to its point of combustion or ignition temperature. This, of course, results in furnace inefficiencies.
A still further problem of the previously-known coal burning furnaces is that such furnaces lose a large amount of heat energy in their exhaust gases and in their steam condensing apparatus for a steam turbine typically used in such furnaces to generate electricity. This energy is unharnessed and thus lost to either the atmosphere or to the rivers or lakes when using water to condense the steam. Additionally, the exhaust from such coal burning furnaces is replete with particulate matter and/or soot. The soot, of course, pollutes the air so that the coal burning furnace must either include an expensive exhaust filtration system or be located away from populated areas.